By Jim Truett, district manager, Miller Electric Mfg. Co.
Edited by Bruce Vernyi, Editor-in-Chief

The Muskeg – a swampy concoction of peat and rotting plant life – has plagued the Canadian oil drilling industry for years.

Yet underneath the deep layers of muck and decay lay vast deposits of the world’s most demanded natural resource. Oil mavericks were finally able to access these oil deposits with the introduction of rigmats: Large planks of wood and steel used to build roads and drilling platforms. Rigmats disperse the weight of trucks and drilling rigs and prevent them from sinking into the bog.

In early 2006, Canadian oil companies approached ITEC Manufacturing USA of Brigham City, Utah to mass-produce rigmats.

Bart Penrod, chief executive officer of ITEC Manufacturing, and Rodney Keller, plant manager for the company, set up a new manufacturing facility in Ogden, Utah with the goal of producing 96 rigmats per day.

ITEC worked with Miller Electric Mfg. Co, Hobart Brothers and Bernard to achieved its goal within three months. It outfitted its new facility with a fully integrated MIG welding system and consumables that could optimize the flow of production.

“The rigmat market is pretty much unlimited for us right now. Because of the techniques we use, we’re able to produce them quicker than most of the companies that have been doing it for a long time,” Keller said.

Manufacturing and Set-Up
ITEC constructs its rigmats with three, 40-foot long, 6 x 15 I-beams that run parallel to each other. It connects each of these I-beams with six cross members that run perpendicular to the main beams.

Fabricators box off each beam with …-in. sheet steel that, when stitch welded in place, make the rigmats look like a pontoon.

The entire frame is constructed of A36 mild steel, and features eye-hooks at four steel crossmember pick points to allow for easy extraction from the muskeg.

Six-by-six wood planks are placed into the center and the f rame and are coped to f i t the beams. Once everything is butted together, the entire frame is welded and the rigmat is complete.

To achieve the production rate of 96 rigmats per day, optimize flow and minimize downtime, ITEC had to address several manufacturing and quality challenges:

• It had to find a MIG welder that would provide the desired output – 650 amps at 100 percent duty cycle.
  
• It had to find a welder that would allow ITEC to tailor the arc start to its application.
  
• It required welder that provide easy access to wire feeders at either end of the 40-foot platforms.
  
• It needed wire feeders that are easy to adjust and provide a consistent feed.
  
• It needed welding wire that have with the appropriate cold and tensile strengths, and could be welded in all positions.
  
• It needed consumables that last long and require minimal downtime for changeovers.

Optimized Arc Starts
After examining the power source and wire feeder needs for its new facility, ITEC chose 20, Deltaweld 652 constant voltage MIG welders. It paired many of those machines with 70 Series wire feeders that are equipped with digital displays and mounted on Swingarc wire feeder booms. Miller Electric manufactures each of these products, and each piece of equipment offers benefits that allow ITEC to streamline production.

While the welders provide the duty cycle ITEC requires, the ability to optimize arc starts by manually changing the machine’s open circuit voltage is one of the best benefits ITEC Manufacturing gets from the equipment.

The equipment has new technology that Keller said allows ITEC Manufacturing to control its starting amperage and starting open circuit voltage to eliminate burnback and burning welding tips.

The machine is preset at 30 volts, but ITEC Manufacturing increased this setting to 32 volts.

The higher open circuit voltage provides a smoother arc start, and ensures that the filler wire is melted by the time it hits the base metal. If the filler wire is driven into the weldment before being completely melted, it can create cat whiskers and/or burnback into the tip. Such discontinuities can lead to costly downtime for weld repairs or changing contact tips.

“My grandpa always told me, ‘If you don’t have time to do it right the first time, when are you going to find time to fix it?’ And because we’re producing 96 rigmats per day, we don’t have any time for rework,” Keller said.

Digital Feeder Consistency
Miller Electric’s 70 Series constant speed wire feeders are mounted on Swingarc booms that are stationed next to each power source. The Swingarc booms are designed with 16-ft. booms that increase an operator’s work envelope, and reduce cable clutter on the floor.

“When we weld a 40-ft. rigmat, we put a fabricator on each end. One guy can swing in 40 feet and overlap another guy without having to move a machine,” Keller said. The work envelope includes the 15 foot welding gun/liner.

However, the most important benefit that the wire feeders provide is the ability to set the welding parameters digitally. That ensures repeatability and consistency from station-to-station and simplifies setting parameters.

“With analog meters, you have one person saying ‘this is set right,’ but then you grab it and it’s set 15 amps or 20 amps colder than what you’re used to. With a digital read-out, the settings are right every time,” Keller said.

Tri-Mark for Mechanical Properties
Next to each of the booms are 600-lb. drums of welding wire. This amount may sound like an excessive amount, but Keller points out that ITEC uses only two wires in this application and that buying in bulk lowers purchase costs. The bulk quantities also reduce downtime associated with changing spools and provides a cleaner feed because the wire is shielded in a drum, not exposed to dust and contaminants in the air.

ITEC uses Tri-Mark .045-in. TM-770 flux cored wire for overhead and out-of-position welding, and Tri-Mark .045- and .052-in. Metalloy 76 metal-cored for welding in flat, horizontal or moderately downhill positions. Both wires are supplied by Hobart Brothers.

“We chose Tri-Mark wires because they provide good tensile strength in cold weather, and we need to create welds that won’t shatter when heavy pipeline equipment drives over them in the middle of the Canadian winter. Regular solid wire can shatter at subzero temperatures, but not Tri- Mark tubular wire,” Keller said.

The TM-770 (an AWS E71T- 1M and E71T-12MJ H8) flux cored wire has a Charpy V-Notch (CVN) toughness of 90 ft-lbs. at -40 degrees F. The Metalloy 76 metal-cored wire (AWS E70C- 6M H4) features a CVN toughness of 34 ft.-lbs. at -40 degrees F. These qualities form strong welds in even the coldest temperatures. Both wires use 85 percent Argon/ 15 percent CO2 shielding gas.

Keller also reports that training welders to run the wires has been easy.

“The Metalloy 76 metal-cored wire enables operators to hold a shorter stick-out. It’s a lot like spray transfer welding with solid wire, so we can put a moderately experienced welder on it, give him a little bit of training and he can produce an impurity-free weld that meets AWS D1.1 standards,” Keller said.

Tips and Jump Liners
ITEC’s welding system features Bernard’s 600 amp Q-Gun with Jump Liners and Centerfire consumables that help the company to reduce downtime associated with changing tips, nozzles and liners.

Bernard’s Centerfire design requires no tools to replace the tip or nozzle, and features a “dropin” contact tip with no threads. The thread-less feature allows quick and easy changeover. The design also includes a large diameter tip base and tapered seat to provide improved electrical conductivity and heat transfer, and a spatter shield within the nozzle helps to ensure smooth gas flow.

“It was really fun to watch people when they first had to change a contact tip. Our welders would pull it off and say ‘it’s broken! It doesn’t have any threads, how am I going to fix it?’ I said ‘just pull it out and put the other one in,’ ” Keller said.

Another source of savings has been Bernard’s Jump Liners. Liners typically wear out at a friction point that is created by the bend of the MIG gun’s neck, and need to be replaced to prevent poor wire feed. Instead of requiring the entire liner to be replaced, Jump Liners allow welders to replace just the area that has been worn – a feature that adds up to a substantial savings in cost and time.

“A Jump Liner can be changed in under a minute. A regular liner could take 15 to 20 minutes to change,” Mike Grimes said. Grimes is the plant foreman for ITEC Manufacturing.

Full Production
ITEC approaches each of its manufacturing challenges with common sense. It looks at its processes from front to back, it examines each step and comes up with new and innovative ways to streamline its processes.

This approach lets Keller and Grimes choose the exact equipment they need – from the power source to the wire to the MIG gun – and integrate the entire process to optimize production flow and minimize operating costs.

“I’ve been in this industry for 45 years. I’ve seen how things go if you don’t plan everything ahead of time. You can’t shoot from your hip. You’ve got to plan it out and decide what’s going to work and how it’s going to work,” Keller said.

The result of this foresight: an operation that has ramped up to full production in three short months.